Needing Help on PC Mod Stuff

So I have recently rekindled my love for the PC version of Minecraft and I want to open a server eventually. Right now I am trying to install mods for my single player game to see if they would be fun on a server with other people or not. I am installing the mods  as described and I do have modloader. The problem is that they are not showing up in the world. I don't  know if I am missing some small detail or what is going on.

The only thing I can think of is that I am having a version clash somewhere. Anyone who has any experience installing mods and making sure they work, I would really appreciate tips or advice.